Liquid dome for storing liquefied gases

Abstract

The present invention relates to a storage facility (1) for liquefied gas and a sealed, insulated liquid tank, comprising: a loading / unloading opening (10) having an upper cover wall (23), a lower cover wall (22) and an insulation structure (24) located between the lower cover wall (22) and the upper cover wall (23), the liquid dome conduit (30) and the upper cover wall (23) being made of different iron-based alloys, and at least one fastening lug (50) extending from the upper cover wall (23) being sealed to a primary sealing membrane (19) directly or indirectly.

Description

Technical Field

[0001] This invention relates to the field of storage facilities for liquefied gases, comprising sealed and insulated membrane-type tanks. In particular, this invention relates to the field of sealed and insulated tanks for storing and / or transporting liquefied gases at cryogenic temperatures, such as tanks for transporting liquefied petroleum gas (GPL) at temperatures, for example, between -50°C and 0°C, or tanks for transporting liquefied natural gas (GNL) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on floating structures. In floating structures, the tanks can be used to transport or receive liquefied gases as fuel to propel the floating structure. Background Technology

[0002] Document FR2991430 describes a storage facility for liquefied gases, comprising sealed, insulated liquid tanks integrated into a supporting structure, which includes a double-hulled ship. Each wall of the liquid tank includes a secondary thermal barrier, a secondary sealing membrane, a primary thermal barrier, and a primary sealing membrane.

[0003] At the top of the liquid tank is a protruding, well-like section known as the liquid dome. In this area, the supporting structure is partially interrupted to define a loading / unloading opening through which the fluid loading / unloading pipeline will pass. This loading / unloading opening, known as the liquid dome, includes insulation or a thermal barrier, as well as elements forming a primary sealing film.

[0004] The goal is to reduce the production cost of such liquid domes, particularly by using lower-cost materials. However, the properties of these lower-cost materials may not be well-suited to the properties of the liquid tank and the very low temperatures that the liquid dome will experience. Furthermore, the liquid tank is installed in a structure subjected to very high mechanical stresses (such as on a ship), which bends and twists according to its environmental conditions. These mechanical stresses are particularly detrimental to the structure of the liquid dome, which is relatively narrow and extends vertically like a shaft above the actual liquid tank containing the liquefied gas.

[0005] Various experiments and tests have demonstrated that liquid dome pipes can be made from low-cost metallic materials, provided that a specific structure is provided to enable the liquid dome to withstand the high stresses applied to it. Summary of the Invention

[0006] This application aims to provide a liquid dome that is low in cost but can withstand all stresses applied to it, while ensuring ideal physical and thermal sealing of the extremely cold fluid contained in the liquid tank.

[0007] Therefore, the present invention relates to a storage facility for liquefied gases, comprising a support structure and a sealed, insulated liquid tank disposed within the support structure. The sealed, insulated liquid tank has a main structure formed by multiple tank walls that are interconnected and secured to a supporting structure. The main structure defines an internal storage space. The main structure includes at least one sealing membrane and at least one thermal barrier, the thermal barrier being positioned between the sealing membrane and the supporting structure. The load-bearing structure has a generally flat upper load-bearing wall. The sealing film, the thermal barrier of the main structure, and the upper support wall are partially interrupted to define a conduit forming the support wall of a wellbore extending along a vertical axis to an upper end, the upper end including a loading / unloading opening for passage of a fluid loading / unloading pipeline, wherein the liquid tank has a cover disposed in the loading / unloading opening, and wherein the cover includes an upper cover wall, a lower cover wall, and a thermal insulation structure located between the lower cover wall and the upper cover wall.

[0008] The invention is characterized in that the pipe and the upper cover are made of different iron-based alloys, and at least one first fastening lug protruding from the upper cover is sealingly fastened to the sealing film.

[0009] Multiple tests and analyses have shown that low-cost carbon steel pipes can be used, provided that special construction is implemented to firmly fix the primary sealing membrane of the liquid dome while allowing a certain degree of freedom to absorb thermal expansion.

[0010] Therefore, the present invention saves a significant amount of money in the construction of the liquid dome, while ensuring or maintaining a perfect seal of the liquefied gas and excellent mechanical strength of the liquid dome against all the stresses that the area is normally subjected to.

[0011] The term "pipeline" refers to the element that forms the outer wall of a liquid dome, or more precisely, the wall that forms the shaft that creates the opening in a liquid tank containing liquefied gas. The term "shaft" refers to the general shape of the liquid dome, which extends vertically from the interior space of the liquid tank itself.

[0012] By convention, referring to the interior and exterior of a liquid tank, the terms "exterior" and "interior" are used to determine the relative position of one element with respect to another element.

[0013] Other advantageous features of the invention are briefly listed below: Advantageously, the sealing film extends from the interior of the internal storage space or the inside of the pipe to the outside of the liquid tank, comprising a primary film and subsequently a secondary film, and is sealed to the secondary film by at least one second fastening lug extending from the upper cover wall.

[0014] In this embodiment, preferably but not exclusively, the first fastening lug and the second fastening lug are independent of each other.

[0015] Therefore, not only is the first fastening lug securely connected to the primary sealing membrane of the liquid dome, but the second fastening lug is also connected to the heat-insulating sealing structure, in this case, to the second sealing membrane. This configuration allows the main structure of the liquid tank to be securely and flexibly fastened to the upper wall of the lid, which, along with its fastening lugs, is made of a material that is particularly resistant to mechanical and thermal stresses.

[0016] Advantageously, the first fastening lug and / or the second fastening lug have an L-shaped cross-section and a linear proximal portion extending from the upper cover wall through a distal portion extending from the proximal portion at an angle of 90±10°, and the primary sealing film or the secondary sealing film is fastened to the proximal portion, respectively.

[0017] According to a preferred embodiment, the distal portions of the first and / or second fastening lugs have a U-shaped or C-shaped profile. This cross-section provides an advantageous degree of elasticity for the first fastening lug and also advantageously for the second fastening lug, which would otherwise be made of a material with inherently low elasticity but excellent mechanical and thermomechanical strength properties.

[0018] According to a preferred embodiment of the present invention, a structural heat insulation element is disposed between the first fastening lug and the second fastening lug, the structural heat insulation element having a heat resistance of at least 200°C, preferably at least 120°C, and more specifically at least 80°C, and preferably, the structural heat insulation element is disposed between the second fastening lug and the pipe.

[0019] Therefore, when the operator performs welding on or near the upper wall of the cover, the first and possibly second fastening lugs help to provide thermal protection for the insulation, which itself has heat-resistant properties. Thus, during the assembly of the liquid dome and its various components, the insulation located at the connection between the main structure of the liquid tank and the liquid dome cover is unlikely to be damaged.

[0020] Therefore, according to an advantageous embodiment, the heat-resistant structural insulation includes: - Enclosed by a structural covering that provides thermal protection, such as glass wool or polyurethane foam. - Glass wool or polyurethane foam surrounded by multiple plywood spacers that provide thermal protection. - Includes a plywood box with glass wool or polyurethane foam for thermal protection. - A plywood box containing glass wool or polyurethane foam at least partially surrounded by a ceramic fiber, aluminum or steel covering, - Glass wool or polyurethane foam surrounded by a plurality of plywood partitions at least partially comprising a ceramic fiber, aluminum or steel covering.

[0021] In the context of the present invention, the expression "structural thermal insulation" for heat resistance is understood to mean that such thermal insulation has mechanical strength properties to resist pressure and all stresses normally applied thereto, so that the thermal insulation has very significant anti-breakage properties without or with little plastic deformation. For example, such structural thermal insulation can withstand a pressure of at least 1 MPa (megapascal). In contrast, non-structural thermal insulation does not have these mechanical strength properties or qualities.

[0022] The exemplary embodiments listed above are not exhaustive, but such thermal insulation must have at least one of the following technical functions, which are listed in decreasing order of importance, preferably at least two of the said functions, and even more preferably all of these technical functions: - Thermal insulation to withstand the heat generated by welding, - Sufficiently mechanically structural to be installed and fastened in a specified space, - Thermal insulation to keep the goods at a low temperature, - Reflect the influence of radiation.

[0023] The actual elements of the implementation of the structural thermal insulation can be combined with a specific welding method, especially the injection of cold inert gas during welding and / or an external radiator during copper bar welding.

[0024] Advantageously, the lower cover wall is not fastened or connected to the first fastening lug. In other words, in this case, the lower cover wall is positioned at a distance from the end of the first fastening lug opposite to the upper cover wall.

[0025] Preferably also with respect to this feature, the lower cover wall is not made of metal or a metal-based alloy, and the lower cover wall is preferably made of plywood. In fact, after analyzing the specific technical background of the present invention, the applicant has noticed that the lower cover wall does not need to have a sealing performance with respect to the fluid contained in the liquid tank.

[0026] Advantageously, the pipe is made of an iron-based alloy, which by weight comprises: 0% < C < 0.21%, 0% < Mn < 1%, 0% < Si < 0.5%, 0% < P < 0.035% and 0% < S < 0.035%, the balance being iron and impurities necessarily resulting from the manufacture of the alloy.

[0027] Preferably, the pipeline is made of steel grades A, B, D, AH, DH, EH, FH or E according to the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC) known to those skilled in the art.

[0028] Advantageously, the upper cover wall and the first fastening lug and optionally the second fastening lug are made of a ferrous alloy including austenitic steel, which by weight has: 0 < C < 0.08%, 0% < Mn ≤ 2%, 0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, 16% < Cr < 50%, 0% < N < 0.02%, optionally 0% ≤ Mo ≤ 3% and / or 0% < Ti < 0.7%, the balance being iron and impurities necessarily resulting from the manufacture of the alloy.

[0029] By convention, the following elements in the periodic table are taken into account: C: carbon, Mn: manganese, Cr: chromium, Si: silicon, Ni: cobalt nickel: Co cobalt, P: phosphorus, O: oxygen, N: nitrogen, Mo: molybdenum, S: sulfur, and Ti: titanium.

[0030] The present invention relates to a ship for transporting cryogenic liquid products, the ship having a double hull and storage facilities arranged in the double hull as described above.

[0031] The present invention also relates to a transfer system for cryogenic liquid products, the system comprising a ship as described above, an insulated pipeline, and a pump, the insulated pipeline being arranged to connect the liquid tank installed in the double hull of the ship to an external onshore or floating storage facility, the pump being used to drive a cryogenic liquid product flow through the insulated pipeline from the external onshore or floating storage facility to the liquid tank on the ship or from the liquid tank of the ship to the external onshore or floating storage facility.

[0032] Finally, the present invention also relates to a method for loading or unloading a ship as described above, wherein a cryogenic liquid product is guided through an insulated pipeline from an external onshore or floating storage facility to the liquid tank on the ship or from the liquid tank on the ship to the external onshore or floating storage facility. Description of the Drawings

[0033] The invention will be better understood and its additional objects, details, features and advantages will be more clearly set forth in the following detailed description of several specific embodiments of the invention, given only as non-limiting examples.

[0034] [ Figure 1 ] Figure 1 This is a schematic diagram of an open liquid dome according to an embodiment of the present invention, wherein two sides or partitions of the pipes and shafts are visible.

[0035] [ Figure 2 ] Figure 2 It is an enlarged cross-sectional view of one side of the pipes and shafts of the liquid dome and the cover of the liquid dome.

[0036] [ Figure 3 ] Figure 3 It is a cross-sectional view of the corner between the cover and the pipe and the liquid dome well, showing in particular the first and second fastening lugs.

[0037] [ Figure 4 ] Figure 4 It is a schematic cross-sectional view showing the corner portion between the cover and the pipe and the liquid dome well in terms of function.

[0038] [ Figure 5 ] Figure 5 yes Figure 4 An enlarged view of the corner portion shown.

[0039] [ Figure 6 ] Figure 6 Is with Figure 1 The diagram shows the first and second fastening lugs, which are particularly visible.

[0040] [ Figure 7 ] Figure 7 Yes Figure 6 The diagram is supplemented with some additional components.

[0041] [ Figure 8 ] Figure 8 Yes Figure 6 The diagram is supplemented with some additional components.

[0042] [ Figure 9 ] Figure 9 This is a cross-sectional schematic diagram of the storage facilities on the ship and the loading / unloading distribution station used for the liquid tank. Detailed Implementation

[0043] In this article, the term "vertical" refers to extension in the direction of Earth's gravitational field. The term "horizontal" refers to extension in a direction perpendicular to the vertical direction.

[0044] When the storage facility 1 is located on a vessel (such as a liquefied natural gas carrier), the load-bearing structure (not shown in the attached drawings) is formed by the vessel's double hull 72. The upper outer load-bearing bulkhead 5 is referred to as the vessel's outer deck 5.

[0045] The sealed, insulated liquid tank 71 includes a main structure comprising a bottom wall (not shown), a top wall, two cofferdam walls (not shown), two side walls (not shown), and optionally two to four sloping walls (not shown). The cofferdam walls connect the bottom wall to the top wall, and when the storage facility 1 is located in a ship, the cofferdam walls are located at the bow and aft. The two to four sloping walls connect the side walls to the bottom or top wall. The walls of the sealed, insulated liquid tank 71 are thus connected to each other to form a polyhedral structure and define an internal storage space 9.

[0046] In order to load and unload the sealed insulated liquid tank 71 containing liquefied gas, the storage facility 1 includes a loading / unloading opening 10 that partially interrupts the upper outer bearing wall 5, the upper inner bearing wall and the top wall of the sealed insulated liquid tank 71, so as to allow loading / unloading lines (not shown in the figures) to pass through the opening 10 to reach the bottom of the sealed insulated liquid tank 71.

[0047] Storage facility 1 also includes a loading / unloading tower (not shown in the figures) located at the same level as opening 10 and inside the sealed insulated liquid tank 71 to form loading / unloading lines and a support structure for a pump (not shown) across the entire height of the sealed insulated liquid tank 71.

[0048] Furthermore, the storage facility 1 has a cover 12 disposed in a loading / unloading opening 10 to close the internal storage space at the opening 10. The cover 12 includes holes for allowing loading / unloading lines to pass through the cover 12.

[0049] The sealed, insulated liquid tank 71 has a well channel 15 located on the main structure at the opening, allowing the tank wall to extend continuously from the inner deck to the outer deck 5 where the wall is interrupted by the loading / unloading opening 10. In a liquefied gas tank, the well channel 15 with the cover 12 is referred to as a liquid dome.

[0050] The loading / unloading opening 10 and the shaft 15 typically have a rectangular outline. The shaft 15 thus includes four walls, one of which is an extension of the rear cofferdam wall 8 (e.g., Figure 1 (as shown), while the other three walls connect to the top wall to form a 90° angle with the top wall.

[0051] According to the present invention, the cover 12 is located on the outer deck 5 to seal the wellbore 15. The sealed insulated liquid tank 71 is a membrane-type sealed insulated liquid tank 71 for storing liquefied gas. The main structure of the sealed insulated liquid tank 71 has a multi-layer structure, which includes, from the outside to the inside, a secondary heat insulation barrier 16, a secondary sealing membrane 17, a primary heat insulation barrier 18, and a primary sealing membrane 19. The secondary heat insulation barrier 16 includes a heat insulation element that abuts against the supporting structure, the secondary sealing membrane 17 abuts against the secondary heat insulation barrier 16, the primary heat insulation barrier 18 includes a heat insulation element that abuts against the secondary sealing membrane 17, and the primary sealing membrane 19 is designed to contact the liquefied gas contained in the sealed insulated liquid tank 71.

[0052] According to one embodiment, the main structure of the sealed, insulated liquid tank 71 uses Mark III. ® The technology is manufactured using a technique described in particular in document FR2691520A.

[0053] In this main structure, the secondary insulation barrier 16, the primary insulation barrier, and the secondary sealing film 17 are generally side-by-side panels on a supporting structure, which can be an internal supporting structure or a structure that connects the upper inner supporting wall to the upper outer supporting wall 5 at the opening 10. The secondary sealing film 17 is made of a composite material comprising an aluminum sheet sandwiched between two sheets of fiberglass fabric. The primary sealing film 19 is obtained by assembling multiple metal plates welded together along their edges and having grooves extending in two perpendicular directions. These metal plates are made, for example, from stainless steel or aluminum sheets by bending or stamping. The primary sealing film 19 is particularly... Figure 3 and Figure 4 As shown in the image.

[0054] Further details of this grooved metal film are described in particular in FR2861060A.

[0055] In the shaft 15, the upper end of the primary sealing film 19 is fastened to the fastening lug 50, and more specifically, to the distal portion 52 of the fastening lug 50. The connection between the fastening lug 50 and the primary film 19 is advantageously formed by sealing welding, or possibly by gluing.

[0056] The cover 12 also includes a multi-layer structure, which from the outside to the inside includes an upper cover wall 23, a lower cover wall 22, and a heat insulation structure 24 located between the lower cover wall 22 and the upper cover wall 23. The cover 12 also has a reinforcing member 25 located on the upper cover wall 23.

[0057] The cover 12 is arranged in the loading / unloading opening 10 such that the upper cover wall 23 is arranged in the plane of the upper outer bearing wall 5 or the outer deck 5. Therefore, in this case, the storage facility 1 does not have a dome base, and the cover 12 does not extend above the outer deck 5.

[0058] The upper cover wall 23 is securely fastened to the outer deck 5 around the entire opening 10, such that the upper cover wall 23 acts as a secondary sealing membrane 17 at the cover 12, or more simply as a sealing membrane, since the applicant has determined the feasibility of using a single sealing membrane in the cover 12. The upper cover wall 23 is made of a metallic material, such as stainless steel.

[0059] According to an important aspect of the invention, the lower cover wall 22 is advantageously made of a non-metallic material or a metallic alloy. In fact, the applicant has determined that such a wall 22 does not necessarily have to be a sealing membrane. Furthermore, the lower cover wall 22 is advantageously made of plywood, but it can also be made of plastic or composite materials (e.g., a "sandwich" structure), preferably thermosetting plastics, provided that the material can mechanically and chemically withstand simple contact with the cold fluid contained in the sealed, insulated liquid tank 71.

[0060] like Figure 4 and Figure 5 As shown, there is no connection between the lower cover wall 22 and the first fastening lug 50 or the primary sealing film 19. Therefore, an opening or gap may exist between the lower cover wall 22 and the primary sealing film 19. Similarly, the applicant has determined that no connection is required between the lower cover wall 22 and the primary sealing film 19.

[0061] The insulation structure 24 of the cover 12 includes multiple insulation elements arranged side-by-side, which may have similar or different structures. In a preferred embodiment, these insulation elements flush with the lower cover wall 22 are structural insulation elements, while insulation elements positioned around the insulation structure 24 (i.e., no insulation element located between walls 22 and 23) are non-structural insulation elements. Of course, structural insulation elements may also be provided between walls 22 and 23 if mechanical stress requirements of the assembly are taken into account. The structural insulation elements may be high-density polymer foam blocks (optionally reinforced with fibers), or plywood or composite boxes filled with insulating fillers such as glass wool or perlite. Non-structural insulation elements may be low-density polymer foam blocks or glass wool.

[0062] However, an important aspect of the present invention relates to heat insulation elements 40 and 41, which are disposed between: - First, a heat insulation element 40, referred to as the heat insulation member, is disposed between the first fastening lug 50 and the second fastening lug 55, and - Secondly, a heat insulation element 41 is provided between the second fastening lug 55 and the pipe 30.

[0063] The insulation components 40 and 41 are structural insulation components. Furthermore, the insulation components 40 and 41 are heat-resistant to temperatures of at least 200°C, and preferably at least 80°C. This means that when exposed to such temperatures, the mechanical properties of the insulation components 40 and 41 do not change or change very little. Therefore, the insulation components 40 and 41, of the aforementioned possible types and functions, are essentially fully capable of resisting the high temperatures caused by nearby welding work. Of course, as mentioned above, the welding work may be accompanied by measures, particularly for the thermal protection of the insulation components 40 and 41, during welding, especially by injecting cold inert gas during welding and / or by providing external radiators during the welding of the copper rods.

[0064] The fastening lug 50 extends vertically from the upper cover wall 23 and includes a vertically linear proximal portion 51 and a distal portion 52, the distal portion 52 extending generally horizontally, or in this case forming a C-shaped hook; however, the distal portion 52 may also have a Γ profile. The fastening lug 50 is advantageously made of the same material as the upper cover wall 23. Therefore, the fastening lug 50 is made of a metallic material (typically an iron-based alloy) that has better mechanical strength than conventional carbon steel (such as the carbon steel of pipe 30) when the ambient temperature is approximately below 0°C, or even equal to or less than -40°C.

[0065] Another important aspect of the invention is the presence of a second fastening lug 55, also extending from the wall 23, for sealingly fastening the second sealing film 17. Thus, within the scope of the invention, each of the two sealing films 17, 19 has an independent sealing connection to the upper cover wall 23 via particularly advantageous fastening lugs 50, 55, which provide high mechanical strength and a degree of flexibility, allowing the lugs to readily absorb various thermomechanical stresses present in a very specific area (i.e., the liquid dome).

[0066] Similar to the first fastening lug 50, the second fastening lug 55 includes a proximal portion 56 and a distal portion 57, the distal portion 57 extending beyond the proximal portion 56, wherein the second sealing film 17 is fastened to the distal portion 57. The distal portion 57 of the second fastening lug 55 has a C-shaped hook profile, but the distal portion 52 may also have a Γ profile. The distal portion 57 is advantageously the same as or may be the same as the distal portion 52 of the first fastening lug 50 in shape and / or size.

[0067] Advantageously, the length of the proximal portion 56 of the second fastening lug 55 is at least twice that of the linear proximal portion 51 of the first fastening lug 50. This feature makes the connection between the wall 23 and the primary sealing film 19 more rigid than the connection between the wall 23 and the secondary sealing film 17, i.e., providing greater flexibility in the connection between the wall 23 and the secondary sealing film 17 than in the connection between the wall 23 and the primary sealing film 19. Generally, it is important that the proximal portion 56 is longer than the linear proximal portion 51 to enable assembly.

[0068] It should be noted here that the present invention primarily relates to the first fastening lug 50 and its direct connection to the primary sealing film 19. Therefore, in an alternative embodiment (not shown in the drawings), the second fastening lug 55 is absent, and the fastening lug 50 additionally includes an arm-like member or flange to securely fasten the fastening lug 50 to the second sealing film 17.

[0069] The upper cover wall 23 and these fastening lugs 50, 55 may be made of 300 series stainless steel approved by IGC rules. In other words, the fastening lugs 50, 55 are made of austenitic steel according to ASTM A240.

[0070] This invention is based first on the fact that the presence of a first fastening lug 50 and possibly a second fastening lug 55 allows the conduit 30 forming the liquid dome 15 to be made of carbon steel, particularly grade A, B, D, AH, DH, EH, FH, or E steel according to ASTM standard A131. Such steels have lower resistance or elasticity when ambient temperatures drop significantly below 0°C, which may present or is confirmed to pose a risk in liquefied gas tanks, but these steels are much less expensive than stainless steel.

[0071] Therefore, this construction reduces the amount of expensive stainless steel in the liquid dome and provides flexibility for the primary anchor (i.e., the primary sealing film 19 at the opening 10 of the liquid dome) and the secondary anchor (i.e., the secondary sealing film 17).

[0072] Therefore, the main aspect of the invention lies in the connection and fastening of the primary sealing film 19 of the liquid dome to the fastening lug 50, and advantageously in the connection and fastening of the secondary sealing film 17 of the liquid dome to the fastening lug 55.

[0073] Furthermore, as previously mentioned, these fastening lugs 50, 55 are offset from the conduit 30 of the liquid dome manhole 15 by at least several centimeters, i.e., offset from the conduit 30 by 5 to 60 cm, preferably by 15 to 40 cm. This offset of the fastening lugs 50, 55 relative to the conduit 30 provides flexible fastening of the membranes 17, 19, allowing the components to easily withstand significant mechanical stresses. It should be noted that when the structure supporting the sealed insulated liquid tank 71 is a ship, this area of ​​the vertically arranged liquid dome manhole 15, which is much smaller or narrower than the sealed insulated liquid tank 71, concentrates intense mechanical stresses and strains.

[0074] As shown in the attached diagram, the offset between the fastening lug 50 and the pipe 30 reduces the need for structural insulation, which is more expensive and more difficult to install than other non-structural insulation. Only structural insulation elements 40 and 41 are needed, respectively, positioned between the fastening lugs 50 and 55 and the partition 30.

[0075] Therefore, compared with conventional liquid domes that do not include fastening lug 50 and may not include fastening lug 55, the amount of structural insulation can be reduced in the liquid dome structure according to the invention.

[0076] Figure 9 An exemplary marine terminal is shown, including a loading / unloading point 75, underwater pipelines 76, and an external onshore or floating storage facility 77. The loading / unloading point 75 is a fixed offshore facility comprising a movable arm 74 and struts 78 supporting the movable arm 74. The movable arm 74 carries a series of insulated hoses 79 that can be connected to a loading / unloading pipe 73. The directional movable arm 74 can be adjusted to accommodate vessels of all sizes. Connecting pipelines (not shown) extend within the struts 78. The loading / unloading point 75 allows a vessel 70 to load or unload cargo from the external onshore or floating storage facility 77. The external onshore or floating storage facility has liquefied gas tanks 80 and connecting pipelines 81 that connect to the loading / unloading point 75 via the underwater pipelines 76. The underwater pipeline 76 enables the transport of liquefied gas over long distances (e.g., 5 km) between the loading / unloading point 75 and the external onshore or floating storage facility 77, which allows the vessel 70 to be kept at a greater distance from the coast during loading and unloading operations.

[0077] To generate the pressure required to transfer liquefied gas, pumps carried on board the vessel 70 and / or installed on external land or floating storage facilities 77 and / or installed at loading / unloading points 75 are used.

[0078] Although the invention has been described in conjunction with several specific embodiments, it is apparent that the invention is not limited thereto, and that the invention will include all technical equivalents of the described components and combinations thereof where such technical equivalents fall within the scope of the invention.

[0079] The use of the verbs “comprise” or “include” and their conjugate forms does not exclude the presence of other elements or steps besides those described in the claims.

[0080] In the claims, the reference numerals enclosed in parentheses should not be construed as limiting the claims.

Claims

1. A storage facility (1) for liquefied gas, comprising a support structure and a sealed, insulated liquid tank (71) disposed within the support structure. The sealed, insulated liquid tank (71) has a main structure formed by multiple tank walls interconnected and fastened to the supporting structure. The main structure defines an internal storage space. The main structure includes at least one sealing membrane (17, 19) and at least one thermal barrier (16, 18), the thermal barrier (16, 18) being positioned between the sealing membrane (17, 19) and the supporting structure. The load-bearing structure has a flat upper load-bearing wall. The sealing film (17, 19), the thermal barrier (16, 18) of the main structure, and the upper support wall are partially interrupted to define a conduit (30) that forms the support wall of a shaft (15) extending along a vertical axis to an upper end, the upper end including a loading / unloading opening (10) for a fluid loading / unloading pipeline to pass through, wherein, The sealed insulated liquid tank (71) has a cover (12) arranged in the loading / unloading opening (10), and wherein the cover (12) includes an upper cover wall (23), a lower cover wall (22) and an insulation structure (24) located between the lower cover wall (22) and the upper cover wall (23). The pipe (30) and the upper cover wall (23) are made of different iron-based alloys, and at least one first fastening lug (50) extending from the upper cover wall (23) is sealed to the sealing film.

2. The storage facility (1) according to claim 1, wherein, The sealing films (17, 19) extending from the interior of the internal storage space or the inside of the pipe (30) to the outside of the sealed heat-insulating tank (71) include: a primary sealing film (19) and a subsequent secondary sealing film (17), and at least one second fastening lug (55) extending from the upper cover wall (23) is sealingly fastened to the secondary sealing film (17).

3. The storage facility (1) according to claim 2, wherein, The first fastening lug (50) and the second fastening lug (55) are independent of each other.

4. The storage facility (1) according to claim 2 or 3, wherein, The first fastening lug (50) and / or the second fastening lug (55) have an L-shaped cross-section and a linear proximal portion (51) extending from the upper cover wall (23) through a distal portion (52) extending from the linear proximal portion (51) at an angle of 90±10°, and the primary sealing film (19) or the secondary sealing film (17) is fastened to the linear proximal portion (51) respectively.

5. The storage facility (1) according to claim 4, wherein, The distal portion of the first fastening lug and / or the second fastening lug has a Γ-shaped or C-shaped profile.

6. The storage facility (1) according to claim 2 or 3, wherein, A structural insulation element is disposed between the first fastening lug (50) and the second fastening lug (55), and the structural insulation element has a heat resistance of at least 200°C.

7. The storage facility (1) according to claim 6, wherein, The heat-resistant structural insulation includes: Glass wool or polyurethane foam surrounded by a structural covering that provides thermal protection. Glass wool or polyurethane foam surrounded by multiple plywood spacers that provide thermal protection. Plywood boxes containing glass wool or polyurethane foam for thermal protection. A plywood box comprising glass wool or polyurethane foam that is at least partially surrounded by a ceramic fiber, aluminum, or steel covering. Glass wool or polyurethane foam surrounded by multiple plywood partitions that at least partially include ceramic fiber, aluminum or steel coverings.

8. The storage facility (1) according to any one of claims 1 to 3, wherein, The lower cover (22) is not fastened or connected to the first fastening lug.

9. The storage facility (1) according to any one of claims 1 to 3, wherein, The lower cover wall (22) is not made of metal or a metal-based alloy.

10. The storage facility (1) according to any one of claims 1 to 3, wherein, The pipe (30) is made of an iron-based alloy, which by weight comprises: 0% < C < 0.21%, 0% < Mn < 1%, 0% < Si < 0.5%, 0% < P < 0.035% and 0% < S < 0.035%, the balance being iron and impurities inevitably resulting from the production of the alloy.

11. The storage facility (1) according to claim 10, wherein, The pipe (30) is made of any one of grades A, B, D, AH, DH, EH, FH or E steel according to IGC rules.

12. The storage facility (1) according to any one of claims 1 to 3, wherein, The upper cover wall (23) and the first fastening lug (50) are made of an iron-based alloy comprising austenitic steel which, by weight, has: 0 < C < 0.08%, 0% < Mn ≤ 2%, 0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, 16% < Cr < 50%, 0% < N < 0.02%, the balance being iron and impurities inevitably resulting from the production of the alloy.

13. The storage facility (1) according to claim 6, wherein, The heat resistance of the structural heat insulator is at least 80 °C.

14. The storage facility (1) according to claim 6, wherein, The structural heat insulator is provided between the second fastening lug and the pipe (30).

15. The storage facility (1) according to claim 9, wherein, The lower cover wall (22) is made of plywood.

16. The storage facility (1) according to claim 2 or 3, wherein, The upper cover wall (23), the first fastening lug (50) and the second fastening lug (55) are made of an iron-based alloy comprising austenitic steel which, by weight, has: 0 < C < 0.08%, 0% < Mn ≤ 2%, 0% < Si < 0.5%, 0% < P < 0.045%, 0% < S < 0.030%, 8% < Ni < 14%, ​ ​ 19. A method for loading or unloading the vessel (70) according to claim 17, wherein, ​

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